Capacity of F1 fuel injectors.

[Tommy Cookers]

the NA F1 engines were feeding on air effectively at 1.25 - 1.3 atmospheres

the hybrid F1 engines are allowed 105 kg of fuel per race

[henry]

Lets try another route.

At 17500rpm a 2.4 litre engine consumes around 380 litres/sec of air ( VE 1.1) which is 465g/sec. Running a little rich, say 13:1 AFR, fuel rate is 36g/sec which is 129kg/hr.

Choose a duty cycle and number of injectors and you can get instantaneous flow rate.

@tommy cookers numbers on air feed pressure will increase these numbers.

[godlameroso]

Lets try another route.

At 17500rpm a 2.4 litre engine consumes around 380 litres/sec of air ( VE 1.1) which is 465g/sec. Running a little rich, say 13:1 AFR, fuel rate is 36g/sec which is 129kg/hr.

Choose a duty cycle and number of injectors and you can get instantaneous flow rate.

@tommy cookers numbers on air feed pressure will increase these numbers.

For a NA car that's actually lean as hell, no way they were running that lean. Most high load applications for all motor calls for ~12.5 - 12.3 and as rich as 10.7 for some engines(the ones with spinning doritos).

[godlameroso]

the NA F1 engines were feeding on air effectively at 1.25 - 1.3 atmospheres

the hybrid F1 engines are allowed 105 kg of fuel per race

110 for 2019?

[henry]

Lets try another route.

At 17500rpm a 2.4 litre engine consumes around 380 litres/sec of air ( VE 1.1) which is 465g/sec. Running a little rich, say 13:1 AFR, fuel rate is 36g/sec which is 129kg/hr.

Choose a duty cycle and number of injectors and you can get instantaneous flow rate.

@tommy cookers numbers on air feed pressure will increase these numbers.

For a NA car that's actually lean as hell, no way they were running that lean. Most high load applications for all motor calls for ~12.5 - 12.3 and as rich as 10.7 for some engines(the ones with spinning doritos).

So at 12.4 we get to 136kg/hr and it doesn’t take much pressurisation of the inlet to get to 150 as quoted by @gruntguru.

[gruntguru]

Lets try another route.

At 17500rpm a 2.4 litre engine consumes around 380 litres/sec of air ( VE 1.1) which is 465g/sec. Running a little rich, say 13:1 AFR, fuel rate is 36g/sec which is 129kg/hr.

Choose a duty cycle and number of injectors and you can get instantaneous flow rate.

@tommy cookers numbers on air feed pressure will increase these numbers.

For a NA car that's actually lean as hell, no way they were running that lean. Most high load applications for all motor calls for ~12.5 - 12.3 and as rich as 10.7 for some engines(the ones with spinning doritos).

13:1 (lambda 0.88) is not "lean as hell". For many modern engines that is best performance AFR.

Time to re-visit the Honda RA 168e paper.https://www.scribd.com/document/1237322 ... 68E-Engine Page 6. Max power AFR at equivalence ratio of 1.15 (lambda 0.87) and that was a turbocharged engine.

[Tommy Cookers]

For a NA car that's actually lean as hell, no way they were running that lean. Most high load applications for all motor calls for ~12.5 - 12.3 and as rich as 10.7 for some engines(the ones with spinning doritos).

13:1 (lambda 0.88) is not "lean as hell". For many modern engines that is best performance AFR.
Time to re-visit the Honda RA 168e paper.https://www.scribd.com/document/1237322 ... 68E-Engine Page 6. Max power AFR at equivalence ratio of 1.15 (lambda 0.87) and that was a turbocharged engine.

lambda 1 is an AFR of 14.1 on E10 gasoline and 14.3 on E5 as we have in the UK (and similarly for Avgas)
so 13:1 will give (in the USA these days) lambda around 0.92

the RA168E was designed to be limited to 2.5 bar abs and iirc 150 litres of 84% toluene/16% heptane fuel
presumably earlier engines using high boost and no formal fuel quantity restriction would have been run richer

aero engines were run eg 60% rich at maximum boost
the Wright Turbocompound paper has a takeoff energy balance diagram showing AFR used
rich mixture (Mr Heron said) lowers flame temperature
and (I say) chemically opposes dissociation and increases benefits of any TEL or similar additives

RETRO-NOTE
chemists complain they can't find a method of calculating stoichiometric ratio
(and engines aren't run on dry air)
some suggest SRs given are empirical values derived from cleanest-exhaust condition on actual engines
BP Australia give 14.7 even for E10 - and 11.5 for toluene

[Bandit1216]

For a NA car that's actually lean as hell, no way they were running that lean. Most high load applications for all motor calls for ~12.5 - 12.3 and as rich as 10.7 for some engines(the ones with spinning doritos).

13:1 (lambda 0.88) is not "lean as hell". For many modern engines that is best performance AFR.
Time to re-visit the Honda RA 168e paper.https://www.scribd.com/document/1237322 ... 68E-Engine Page 6. Max power AFR at equivalence ratio of 1.15 (lambda 0.87) and that was a turbocharged engine.

lambda 1 is an AFR of 14.1 on E10 gasoline and 14.3 on E5 as we have in the UK (and similarly for Avgas)
so 13:1 will give (in the USA these days) lambda around 0.92

the RA168E was designed to be limited to 2.5 bar abs and iirc 150 litres of 84% toluene/16% heptane fuel
presumably earlier engines using high boost and no formal fuel quantity restriction would have been run richer

aero engines were run eg 60% rich at maximum boost
the Wright Turbocompound paper has a takeoff energy balance diagram showing AFR used
rich mixture (Mr Heron said) lowers flame temperature
and (I say) chemically opposes dissociation and increases benefits of any TEL or similar additives

Can't remember where, but years ago I read that the unlimited boosted F1 engines ran about 0,7 lambda. For cooling that is. This article was about the BMW

[godlameroso]

That's about right for FI, the f22c and F20c's I tune love to run 12.2 12.3 on boost. GG you are right, I just looked at some tunes I did for all motor cars and they were in the low 13's.

Stochiometry is a theoretical number, you will never achieve it. IE, you will never have a 100% reaction

[gruntguru]

For a NA car that's actually lean as hell, no way they were running that lean. Most high load applications for all motor calls for ~12.5 - 12.3 and as rich as 10.7 for some engines(the ones with spinning doritos).

13:1 (lambda 0.88) is not "lean as hell". For many modern engines that is best performance AFR.
Time to re-visit the Honda RA 168e paper.https://www.scribd.com/document/1237322 ... 68E-Engine Page 6. Max power AFR at equivalence ratio of 1.15 (lambda 0.87) and that was a turbocharged engine.

the RA168E was designed to be limited to 2.5 bar abs and iirc 150 litres of 84% toluene/16% heptane fuel
presumably earlier engines using high boost and no formal fuel quantity restriction would have been run richer

Best power mixture for the RA168e was 0.87 and would have been similar for other (conventional) fuel of equal knock resistance. Richer mixtures would cost power. The lost power (and some) might be recovered by increasing boost, CR or spark advance due to the improved knock resistance and thermal stress offered by richer mix. (Of course the rules did not permit more boost and a richer mix would have increased fuel consumption which was also regulated)

aero engines were run eg 60% rich at maximum boost the Wright Turbocompound paper has a takeoff energy balance diagram showing AFR used rich mixture (Mr Heron said) lowers flame temperature and (I say) chemically opposes dissociation and increases benefits of any TEL or similar additives

Again the rich mixture is not increasing power - it is enabling higher boost and ensuring durability. Any leaning of the Wright TC under takeoff conditions would increase power. It might need higher octane fuel and it might reduce engine durability, but it would increase power.

[Dr. Acula]

13:1 (lambda 0.88) is not "lean as hell". For many modern engines that is best performance AFR.
Time to re-visit the Honda RA 168e paper.https://www.scribd.com/document/1237322 ... 68E-Engine Page 6. Max power AFR at equivalence ratio of 1.15 (lambda 0.87) and that was a turbocharged engine.

the RA168E was designed to be limited to 2.5 bar abs and iirc 150 litres of 84% toluene/16% heptane fuel
presumably earlier engines using high boost and no formal fuel quantity restriction would have been run richer

Best power mixture for the RA168e was 0.87 and would have been similar for other (conventional) fuel of equal knock resistance. Richer mixtures would cost power. The lost power (and some) might be recovered by increasing boost, CR or spark advance due to the improved knock resistance and thermal stress offered by richer mix. (Of course the rules did not permit more boost and a richer mix would have increased fuel consumption which was also regulated)

Well, there was a Problem with the equivalence ratio of 1.15 as you can read on Page 6 of the Paper.

Effect of Air Fuel Ratio-
Regarding air fuel ratio, peak power is reached at an equivalence ratio of 1.15 and power gradually decreases as the ratio falls below this figure. The leaner the mixture becomes, the better the B.S.F.C., as shown in Fig. 12. Howerver, with a ratio lower than 1.02. unsatisfactory transient response may appear, thus making the engine become insufficient for racing performance.

and on page 7 they stated

A combination of operating factors to achieve the best B.S.F.C., while maintaining satisfactory performance, is an intake air temperature of 70°C, a boost of 2.5 bar, an equivalence ration of 1.02 and fuel temperature of 80°C. With this combination, B.S.F.C. is 272g/kWh (200g/psh) at 12'000rpm.

So as i understand it, the RA168E could run with an equivalence ratio of 1.15 on the dyno and regarding poweroutput it was superior to a richer mixture, but it was so much on the edge of what the system as a whole could handle that if the mixture just got slithly leaner for instance because of a sudden change of throttle position, they experienced massive power drops. So they never used that in the real world.

[Tommy Cookers]

aero engines were run eg 60% rich at maximum boost the Wright Turbocompound paper has a takeoff energy balance diagram showing AFR used rich mixture (Mr Heron said) lowers flame temperature and (I say) chemically opposes dissociation and increases benefits of any TEL or similar additives

Again the rich mixture is not increasing power - it is enabling higher boost and ensuring durability. Any leaning of the Wright TC under takeoff conditions would increase power. It might need higher octane fuel and it might reduce engine durability, but it would increase power.

it might appear to increase power if the boost was fixed (necessarily at a lower level than was used with rich mixture)
but this also ignores the reduction with rich mixture of CO2 dissociation (this presumably greater in a low rpm engine)
and the 'Rankine power' of the surplus fuel boiling during the power stroke

an argument against richness (and PI or carburettors) is the less favourable ratio of in-cycle specific heats
and of course without DI over-richness is the amount of richness that displaces too much charge air
(why NA aircraft engines have scope for richness giving sub-optimal power WOT at altitude - maybe Steve Fossett's ???)


what I have only recently learned is that stoichiometric ratio is seemingly not chemically referenced
presumably because chemistry must assume fuel is the only thing that is burned a '14.7' gasoline is '15.1' chemically
but real engines appear to burn some of the air's nitrogen
EDIT and real engines run on air with eg 1% - 5% water vapour content
so lambda = 1 is subjective for engineering purposes and not rigorously derived
now it may just be the artificial slightly low value that the current oxygen sensor-driven fuelling loop develops
so one engine's 0.88 lambda may not be the same as another engines 0.88 lambda

[gruntguru]

the RA168E was designed to be limited to 2.5 bar abs and iirc 150 litres of 84% toluene/16% heptane fuel
presumably earlier engines using high boost and no formal fuel quantity restriction would have been run richer

Best power mixture for the RA168e was 0.87 and would have been similar for other (conventional) fuel of equal knock resistance. Richer mixtures would cost power. The lost power (and some) might be recovered by increasing boost, CR or spark advance due to the improved knock resistance and thermal stress offered by richer mix. (Of course the rules did not permit more boost and a richer mix would have increased fuel consumption which was also regulated)

Well, there was a Problem with the equivalence ratio of 1.15 as you can read on Page 6 of the Paper.

Effect of Air Fuel Ratio-
Regarding air fuel ratio, peak power is reached at an equivalence ratio of 1.15 and power gradually decreases as the ratio falls below this figure. The leaner the mixture becomes, the better the B.S.F.C., as shown in Fig. 12. Howerver, with a ratio lower than 1.02. unsatisfactory transient response may appear, thus making the engine become insufficient for racing performance.

and on page 7 they stated

A combination of operating factors to achieve the best B.S.F.C., while maintaining satisfactory performance, is an intake air temperature of 70°C, a boost of 2.5 bar, an equivalence ration of 1.02 and fuel temperature of 80°C. With this combination, B.S.F.C. is 272g/kWh (200g/psh) at 12'000rpm.

So as i understand it, the RA168E could run with an equivalence ratio of 1.15 on the dyno and regarding poweroutput it was superior to a richer mixture, but it was so much on the edge of what the system as a whole could handle that if the mixture just got slithly leaner for instance because of a sudden change of throttle position, they experienced massive power drops. So they never used that in the real world.

1.15 ER is richer than 1.02 ER. ER = 1/lambda

On the track the WOT ER for the RA168e was 1.02 for economy and 1.15 for power. At 1.15 ER the engine made 6.5% more power and used fuel at a 16.5% higher rate. (about 9.3% worse efficiency)

[gruntguru]

aero engines were run eg 60% rich at maximum boost the Wright Turbocompound paper has a takeoff energy balance diagram showing AFR used rich mixture (Mr Heron said) lowers flame temperature and (I say) chemically opposes dissociation and increases benefits of any TEL or similar additives

Again the rich mixture is not increasing power - it is enabling higher boost and ensuring durability. Any leaning of the Wright TC under takeoff conditions would increase power. It might need higher octane fuel and it might reduce engine durability, but it would increase power.

it might appear to increase power if the boost was fixed (necessarily at a lower level than was used with rich mixture) but this also ignores the reduction with rich mixture of CO2 dissociation (this presumably greater in a low rpm engine)

Not sure what you are getting at here? ("appear to increase power") The dynamometer doesn't lie.

and the 'Rankine power' of the surplus fuel boiling during the power stroke

I remember doing the calculations for the so called "Rankine" effect for water injection. It doesn't exist - the heat consumed in vaporising the water would do more work if used to heat the combustion gases. No doubt the same applies for vaporising excess fuel.

[Dr. Acula]

Best power mixture for the RA168e was 0.87 and would have been similar for other (conventional) fuel of equal knock resistance. Richer mixtures would cost power. The lost power (and some) might be recovered by increasing boost, CR or spark advance due to the improved knock resistance and thermal stress offered by richer mix. (Of course the rules did not permit more boost and a richer mix would have increased fuel consumption which was also regulated)

Well, there was a Problem with the equivalence ratio of 1.15 as you can read on Page 6 of the Paper.

Effect of Air Fuel Ratio-
Regarding air fuel ratio, peak power is reached at an equivalence ratio of 1.15 and power gradually decreases as the ratio falls below this figure. The leaner the mixture becomes, the better the B.S.F.C., as shown in Fig. 12. Howerver, with a ratio lower than 1.02. unsatisfactory transient response may appear, thus making the engine become insufficient for racing performance.

and on page 7 they stated

A combination of operating factors to achieve the best B.S.F.C., while maintaining satisfactory performance, is an intake air temperature of 70°C, a boost of 2.5 bar, an equivalence ration of 1.02 and fuel temperature of 80°C. With this combination, B.S.F.C. is 272g/kWh (200g/psh) at 12'000rpm.

So as i understand it, the RA168E could run with an equivalence ratio of 1.15 on the dyno and regarding poweroutput it was superior to a richer mixture, but it was so much on the edge of what the system as a whole could handle that if the mixture just got slithly leaner for instance because of a sudden change of throttle position, they experienced massive power drops. So they never used that in the real world.

1.15 ER is richer than 1.02 ER. ER = 1/lambda

On the track the WOT ER for the RA168e was 1.02 for economy and 1.15 for power. At 1.15 ER the engine made 6.5% more power and used fuel at a 16.5% higher rate. (about 9.3% worse efficiency)

Ohh
Seems i was a bit confused about that. Thank for the clarification.